A hidden device detects and counts shoppers that enter a store. A slight flaw in the device produces some errors in counting when two shoppers enter the store close the same time. When two shoppers enter a store together, one walking in
front of the other there is a 0.98 probability that
the first shopper will be detected, a 0.94 probability that the second shopper will be
detected and a 0.93 probability that both of them will be detected and counted by the device.
What is the probability that the device will detect at least one of the two shoppers
entering together?